/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright (c) 2011, 2012, Intel Corporation.
 *
 *   Author: Zach Brown <zab@zabbo.net>
 *   Author: Peter J. Braam <braam@clusterfs.com>
 *   Author: Phil Schwan <phil@clusterfs.com>
 *   Author: Eric Barton <eric@bartonsoftware.com>
 *
 *   This file is part of Lustre, http://www.lustre.org
 *
 *   Portals is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Portals is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Portals; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#define DEBUG_PORTAL_ALLOC
#define DEBUG_SUBSYSTEM S_LND

#include "socklnd_lib-linux.h"

#include "../../../include/linux/libcfs/libcfs.h"
#include "../../../include/linux/lnet/lnet.h"
#include "../../../include/linux/lnet/lib-lnet.h"
#include "../../../include/linux/lnet/socklnd.h"
#include "../../../include/linux/lnet/lnet-sysctl.h"

#define SOCKNAL_PEER_HASH_SIZE  101          /* # peer lists */
#define SOCKNAL_RESCHED  100         /* # scheduler loops before reschedule */
#define SOCKNAL_INSANITY_RECONN 5000        /* connd is trying on reconn infinitely */
#define SOCKNAL_ENOMEM_RETRY    CFS_TICK        /* jiffies between retries */

#define SOCKNAL_SINGLE_FRAG_TX      0      /* disable multi-fragment sends */
#define SOCKNAL_SINGLE_FRAG_RX      0      /* disable multi-fragment receives */

#define SOCKNAL_VERSION_DEBUG       0      /* enable protocol version debugging */

/* risk kmap deadlock on multi-frag I/O (backs off to single-frag if disabled).
 * no risk if we're not running on a CONFIG_HIGHMEM platform. */
#ifdef CONFIG_HIGHMEM
# define SOCKNAL_RISK_KMAP_DEADLOCK  0
#else
# define SOCKNAL_RISK_KMAP_DEADLOCK  1
#endif

struct ksock_sched_info;

typedef struct                            /* per scheduler state */
{
        spinlock_t              kss_lock;       /* serialise */
        struct list_head                kss_rx_conns;   /* conn waiting to be read */
        /* conn waiting to be written */
        struct list_head                kss_tx_conns;
        /* zombie noop tx list */
        struct list_head                kss_zombie_noop_txs;
        wait_queue_head_t               kss_waitq;      /* where scheduler sleeps */
        /* # connections assigned to this scheduler */
        int                     kss_nconns;
        struct ksock_sched_info *kss_info;      /* owner of it */
        struct page             *kss_rx_scratch_pgs[LNET_MAX_IOV];
        struct kvec             kss_scratch_iov[LNET_MAX_IOV];
} ksock_sched_t;

struct ksock_sched_info {
        int                     ksi_nthreads_max; /* max allowed threads */
        int                     ksi_nthreads;   /* number of threads */
        int                     ksi_cpt;        /* CPT id */
        ksock_sched_t           *ksi_scheds;    /* array of schedulers */
};

#define KSOCK_CPT_SHIFT                 16
#define KSOCK_THREAD_ID(cpt, sid)       (((cpt) << KSOCK_CPT_SHIFT) | (sid))
#define KSOCK_THREAD_CPT(id)            ((id) >> KSOCK_CPT_SHIFT)
#define KSOCK_THREAD_SID(id)            ((id) & ((1UL << KSOCK_CPT_SHIFT) - 1))

typedef struct                            /* in-use interface */
{
        __u32           ksni_ipaddr;            /* interface's IP address */
        __u32           ksni_netmask;           /* interface's network mask */
        int             ksni_nroutes;           /* # routes using (active) */
        int             ksni_npeers;            /* # peers using (passive) */
        char            ksni_name[IFNAMSIZ];    /* interface name */
} ksock_interface_t;

typedef struct {
        /* "stuck" socket timeout (seconds) */
        int           *ksnd_timeout;
        /* # scheduler threads in each pool while starting */
        int              *ksnd_nscheds;
        int           *ksnd_nconnds;     /* # connection daemons */
        int           *ksnd_nconnds_max;     /* max # connection daemons */
        int           *ksnd_min_reconnectms; /* first connection retry after (ms)... */
        int           *ksnd_max_reconnectms; /* ...exponentially increasing to this */
        int           *ksnd_eager_ack;       /* make TCP ack eagerly? */
        int           *ksnd_typed_conns;     /* drive sockets by type? */
        int           *ksnd_min_bulk;   /* smallest "large" message */
        int           *ksnd_tx_buffer_size;  /* socket tx buffer size */
        int           *ksnd_rx_buffer_size;  /* socket rx buffer size */
        int           *ksnd_nagle;         /* enable NAGLE? */
        int           *ksnd_round_robin;     /* round robin for multiple interfaces */
        int           *ksnd_keepalive;       /* # secs for sending keepalive NOOP */
        int           *ksnd_keepalive_idle;  /* # idle secs before 1st probe */
        int           *ksnd_keepalive_count; /* # probes */
        int           *ksnd_keepalive_intvl; /* time between probes */
        int           *ksnd_credits;     /* # concurrent sends */
        int           *ksnd_peertxcredits;   /* # concurrent sends to 1 peer */
        int           *ksnd_peerrtrcredits;  /* # per-peer router buffer credits */
        int           *ksnd_peertimeout;     /* seconds to consider peer dead */
        int           *ksnd_enable_csum;     /* enable check sum */
        int           *ksnd_inject_csum_error; /* set non-zero to inject checksum error */
        int           *ksnd_nonblk_zcack;    /* always send zc-ack on non-blocking connection */
        unsigned int     *ksnd_zc_min_payload;  /* minimum zero copy payload size */
        int           *ksnd_zc_recv;     /* enable ZC receive (for Chelsio TOE) */
        int           *ksnd_zc_recv_min_nfrags; /* minimum # of fragments to enable ZC receive */
} ksock_tunables_t;

typedef struct {
        __u64             ksnn_incarnation;     /* my epoch */
        spinlock_t        ksnn_lock;            /* serialise */
        struct list_head          ksnn_list;            /* chain on global list */
        int               ksnn_npeers;          /* # peers */
        int               ksnn_shutdown;        /* shutting down? */
        int               ksnn_ninterfaces;     /* IP interfaces */
        ksock_interface_t ksnn_interfaces[LNET_MAX_INTERFACES];
} ksock_net_t;

/** connd timeout */
#define SOCKNAL_CONND_TIMEOUT  120
/** reserved thread for accepting & creating new connd */
#define SOCKNAL_CONND_RESV     1

typedef struct {
        int                     ksnd_init;      /* initialisation state */
        int                     ksnd_nnets;     /* # networks set up */
        struct list_head                ksnd_nets;      /* list of nets */
        /* stabilize peer/conn ops */
        rwlock_t                ksnd_global_lock;
        /* hash table of all my known peers */
        struct list_head                *ksnd_peers;
        int                     ksnd_peer_hash_size; /* size of ksnd_peers */

        int                     ksnd_nthreads;  /* # live threads */
        int                     ksnd_shuttingdown; /* tell threads to exit */
        /* schedulers information */
        struct ksock_sched_info **ksnd_sched_info;

        atomic_t      ksnd_nactive_txs;    /* #active txs */

        struct list_head        ksnd_deathrow_conns; /* conns to close: reaper_lock*/
        struct list_head        ksnd_zombie_conns;   /* conns to free: reaper_lock */
        struct list_head        ksnd_enomem_conns;   /* conns to retry: reaper_lock*/
        wait_queue_head_t       ksnd_reaper_waitq;   /* reaper sleeps here */
        unsigned long   ksnd_reaper_waketime;/* when reaper will wake */
        spinlock_t        ksnd_reaper_lock;     /* serialise */

        int            ksnd_enomem_tx;      /* test ENOMEM sender */
        int            ksnd_stall_tx;       /* test sluggish sender */
        int            ksnd_stall_rx;       /* test sluggish receiver */

        struct list_head        ksnd_connd_connreqs; /* incoming connection requests */
        struct list_head        ksnd_connd_routes;   /* routes waiting to be connected */
        wait_queue_head_t       ksnd_connd_waitq;    /* connds sleep here */
        int            ksnd_connd_connecting;/* # connds connecting */
        /** time stamp of the last failed connecting attempt */
        long          ksnd_connd_failed_stamp;
        /** # starting connd */
        unsigned          ksnd_connd_starting;
        /** time stamp of the last starting connd */
        long          ksnd_connd_starting_stamp;
        /** # running connd */
        unsigned          ksnd_connd_running;
        spinlock_t        ksnd_connd_lock;      /* serialise */

        struct list_head          ksnd_idle_noop_txs;   /* list head for freed noop tx */
        spinlock_t        ksnd_tx_lock;         /* serialise, g_lock unsafe */

} ksock_nal_data_t;

#define SOCKNAL_INIT_NOTHING    0
#define SOCKNAL_INIT_DATA       1
#define SOCKNAL_INIT_ALL        2

/* A packet just assembled for transmission is represented by 1 or more
 * struct iovec fragments (the first frag contains the portals header),
 * followed by 0 or more lnet_kiov_t fragments.
 *
 * On the receive side, initially 1 struct iovec fragment is posted for
 * receive (the header).  Once the header has been received, the payload is
 * received into either struct iovec or lnet_kiov_t fragments, depending on
 * what the header matched or whether the message needs forwarding. */

struct ksock_conn;                            /* forward ref */
struct ksock_peer;                            /* forward ref */
struct ksock_route;                          /* forward ref */
struct ksock_proto;                          /* forward ref */

typedef struct                            /* transmit packet */
{
        struct list_head     tx_list;   /* queue on conn for transmission etc */
        struct list_head     tx_zc_list;     /* queue on peer for ZC request */
        atomic_t   tx_refcount;    /* tx reference count */
        int         tx_nob;      /* # packet bytes */
        int         tx_resid;       /* residual bytes */
        int         tx_niov;    /* # packet iovec frags */
        struct kvec  *tx_iov;    /* packet iovec frags */
        int         tx_nkiov;       /* # packet page frags */
        unsigned short tx_zc_aborted;  /* aborted ZC request */
        unsigned short tx_zc_capable:1; /* payload is large enough for ZC */
        unsigned short tx_zc_checked:1; /* Have I checked if I should ZC? */
        unsigned short tx_nonblk:1;    /* it's a non-blocking ACK */
        lnet_kiov_t   *tx_kiov; /* packet page frags */
        struct ksock_conn  *tx_conn;    /* owning conn */
        lnet_msg_t    *tx_lnetmsg;     /* lnet message for lnet_finalize() */
        unsigned long     tx_deadline;    /* when (in jiffies) tx times out */
        ksock_msg_t    tx_msg;   /* socklnd message buffer */
        int         tx_desc_size;   /* size of this descriptor */
        union {
                struct {
                        struct kvec iov;       /* virt hdr */
                        lnet_kiov_t  kiov[0];   /* paged payload */
                }                 paged;
                struct {
                        struct kvec iov[1];    /* virt hdr + payload */
                }                 virt;
        }                      tx_frags;
} ksock_tx_t;

#define KSOCK_NOOP_TX_SIZE  ((int)offsetof(ksock_tx_t, tx_frags.paged.kiov[0]))

/* network zero copy callback descriptor embedded in ksock_tx_t */

/* space for the rx frag descriptors; we either read a single contiguous
 * header, or up to LNET_MAX_IOV frags of payload of either type. */
typedef union {
        struct kvec      iov[LNET_MAX_IOV];
        lnet_kiov_t      kiov[LNET_MAX_IOV];
} ksock_rxiovspace_t;

#define SOCKNAL_RX_KSM_HEADER   1              /* reading ksock message header */
#define SOCKNAL_RX_LNET_HEADER  2              /* reading lnet message header */
#define SOCKNAL_RX_PARSE        3              /* Calling lnet_parse() */
#define SOCKNAL_RX_PARSE_WAIT   4              /* waiting to be told to read the body */
#define SOCKNAL_RX_LNET_PAYLOAD 5              /* reading lnet payload (to deliver here) */
#define SOCKNAL_RX_SLOP  6             /* skipping body */

typedef struct ksock_conn {
        struct ksock_peer  *ksnc_peer;   /* owning peer */
        struct ksock_route *ksnc_route; /* owning route */
        struct list_head          ksnc_list;     /* stash on peer's conn list */
        struct socket       *ksnc_sock;  /* actual socket */
        void           *ksnc_saved_data_ready; /* socket's original data_ready() callback */
        void           *ksnc_saved_write_space; /* socket's original write_space() callback */
        atomic_t        ksnc_conn_refcount; /* conn refcount */
        atomic_t        ksnc_sock_refcount; /* sock refcount */
        ksock_sched_t      *ksnc_scheduler;  /* who schedules this connection */
        __u32          ksnc_myipaddr;   /* my IP */
        __u32          ksnc_ipaddr;     /* peer's IP */
        int              ksnc_port;       /* peer's port */
        signed int        ksnc_type:3;     /* type of connection,
                                              * should be signed value */
        unsigned int        ksnc_closing:1;  /* being shut down */
        unsigned int        ksnc_flip:1;     /* flip or not, only for V2.x */
        unsigned int        ksnc_zc_capable:1; /* enable to ZC */
        struct ksock_proto *ksnc_proto;      /* protocol for the connection */

        /* reader */
        struct list_head  ksnc_rx_list;     /* where I enq waiting input or a forwarding descriptor */
        unsigned long       ksnc_rx_deadline; /* when (in jiffies) receive times out */
        __u8              ksnc_rx_started;  /* started receiving a message */
        __u8              ksnc_rx_ready;    /* data ready to read */
        __u8              ksnc_rx_scheduled;/* being progressed */
        __u8              ksnc_rx_state;    /* what is being read */
        int                ksnc_rx_nob_left; /* # bytes to next hdr/body */
        int                ksnc_rx_nob_wanted; /* bytes actually wanted */
        int                ksnc_rx_niov;     /* # iovec frags */
        struct kvec      *ksnc_rx_iov;      /* the iovec frags */
        int                ksnc_rx_nkiov;    /* # page frags */
        lnet_kiov_t       *ksnc_rx_kiov;     /* the page frags */
        ksock_rxiovspace_t    ksnc_rx_iov_space;/* space for frag descriptors */
        __u32            ksnc_rx_csum;     /* partial checksum for incoming data */
        void             *ksnc_cookie;      /* rx lnet_finalize passthru arg */
        ksock_msg_t        ksnc_msg;     /* incoming message buffer:
                                                 * V2.x message takes the
                                                 * whole struct
                                                 * V1.x message is a bare
                                                 * lnet_hdr_t, it's stored in
                                                 * ksnc_msg.ksm_u.lnetmsg */

        /* WRITER */
        struct list_head            ksnc_tx_list;     /* where I enq waiting for output space */
        struct list_head            ksnc_tx_queue;    /* packets waiting to be sent */
        ksock_tx_t         *ksnc_tx_carrier;  /* next TX that can carry a LNet message or ZC-ACK */
        unsigned long       ksnc_tx_deadline; /* when (in jiffies) tx times out */
        int                ksnc_tx_bufnob;     /* send buffer marker */
        atomic_t          ksnc_tx_nob;  /* # bytes queued */
        int                ksnc_tx_ready;      /* write space */
        int                ksnc_tx_scheduled;  /* being progressed */
        unsigned long       ksnc_tx_last_post;  /* time stamp of the last posted TX */
} ksock_conn_t;

typedef struct ksock_route {
        struct list_head            ksnr_list;  /* chain on peer route list */
        struct list_head            ksnr_connd_list;  /* chain on ksnr_connd_routes */
        struct ksock_peer    *ksnr_peer;        /* owning peer */
        atomic_t          ksnr_refcount;    /* # users */
        unsigned long       ksnr_timeout;     /* when (in jiffies) reconnection can happen next */
        long    ksnr_retry_interval; /* how long between retries */
        __u32            ksnr_myipaddr;    /* my IP */
        __u32            ksnr_ipaddr;      /* IP address to connect to */
        int                ksnr_port;   /* port to connect to */
        unsigned int      ksnr_scheduled:1; /* scheduled for attention */
        unsigned int      ksnr_connecting:1;/* connection establishment in progress */
        unsigned int      ksnr_connected:4; /* connections established by type */
        unsigned int      ksnr_deleted:1;   /* been removed from peer? */
        unsigned int      ksnr_share_count; /* created explicitly? */
        int                ksnr_conn_count;  /* # conns established by this route */
} ksock_route_t;

#define SOCKNAL_KEEPALIVE_PING    1       /* cookie for keepalive ping */

typedef struct ksock_peer {
        struct list_head            ksnp_list;  /* stash on global peer list */
        unsigned long       ksnp_last_alive;  /* when (in jiffies) I was last alive */
        lnet_process_id_t     ksnp_id;       /* who's on the other end(s) */
        atomic_t          ksnp_refcount; /* # users */
        int                ksnp_sharecount;  /* lconf usage counter */
        int                ksnp_closing;  /* being closed */
        int                ksnp_accepting;/* # passive connections pending */
        int                ksnp_error;    /* errno on closing last conn */
        __u64            ksnp_zc_next_cookie;/* ZC completion cookie */
        __u64            ksnp_incarnation;   /* latest known peer incarnation */
        struct ksock_proto   *ksnp_proto;    /* latest known peer protocol */
        struct list_head            ksnp_conns;    /* all active connections */
        struct list_head            ksnp_routes;   /* routes */
        struct list_head            ksnp_tx_queue; /* waiting packets */
        spinlock_t            ksnp_lock;        /* serialize, g_lock unsafe */
        struct list_head            ksnp_zc_req_list;   /* zero copy requests wait for ACK  */
        unsigned long       ksnp_send_keepalive; /* time to send keepalive */
        lnet_ni_t           *ksnp_ni;       /* which network */
        int                ksnp_n_passive_ips; /* # of... */
        __u32            ksnp_passive_ips[LNET_MAX_INTERFACES]; /* preferred local interfaces */
} ksock_peer_t;

typedef struct ksock_connreq {
        struct list_head            ksncr_list;     /* stash on ksnd_connd_connreqs */
        lnet_ni_t           *ksncr_ni;       /* chosen NI */
        struct socket    *ksncr_sock;     /* accepted socket */
} ksock_connreq_t;

extern ksock_nal_data_t ksocknal_data;
extern ksock_tunables_t ksocknal_tunables;

#define SOCKNAL_MATCH_NO        0       /* TX can't match type of connection */
#define SOCKNAL_MATCH_YES       1       /* TX matches type of connection */
#define SOCKNAL_MATCH_MAY       2       /* TX can be sent on the connection, but not preferred */

typedef struct ksock_proto {
        int        pro_version;                                       /* version number of protocol */
        int      (*pro_send_hello)(ksock_conn_t *, ksock_hello_msg_t *);     /* handshake function */
        int      (*pro_recv_hello)(ksock_conn_t *, ksock_hello_msg_t *, int);/* handshake function */
        void    (*pro_pack)(ksock_tx_t *);                                /* message pack */
        void    (*pro_unpack)(ksock_msg_t *);                          /* message unpack */
        ksock_tx_t *(*pro_queue_tx_msg)(ksock_conn_t *, ksock_tx_t *);    /* queue tx on the connection */
        int      (*pro_queue_tx_zcack)(ksock_conn_t *, ksock_tx_t *, __u64); /* queue ZC ack on the connection */
        int      (*pro_handle_zcreq)(ksock_conn_t *, __u64, int);           /* handle ZC request */
        int      (*pro_handle_zcack)(ksock_conn_t *, __u64, __u64);       /* handle ZC ACK */
        int      (*pro_match_tx)(ksock_conn_t *, ksock_tx_t *, int);     /* msg type matches the connection type:
                                                                                 * return value:
                                                                                 *   return MATCH_NO  : no
                                                                                 *   return MATCH_YES : matching type
                                                                                 *   return MATCH_MAY : can be backup */
} ksock_proto_t;

extern ksock_proto_t ksocknal_protocol_v1x;
extern ksock_proto_t ksocknal_protocol_v2x;
extern ksock_proto_t ksocknal_protocol_v3x;

#define KSOCK_PROTO_V1_MAJOR    LNET_PROTO_TCP_VERSION_MAJOR
#define KSOCK_PROTO_V1_MINOR    LNET_PROTO_TCP_VERSION_MINOR
#define KSOCK_PROTO_V1    KSOCK_PROTO_V1_MAJOR

#ifndef CPU_MASK_NONE
#define CPU_MASK_NONE   0UL
#endif

static inline int
ksocknal_route_mask(void)
{
        if (!*ksocknal_tunables.ksnd_typed_conns)
                return (1 << SOCKLND_CONN_ANY);

        return ((1 << SOCKLND_CONN_CONTROL) |
                (1 << SOCKLND_CONN_BULK_IN) |
                (1 << SOCKLND_CONN_BULK_OUT));
}

static inline struct list_head *
ksocknal_nid2peerlist(lnet_nid_t nid)
{
        unsigned int hash = ((unsigned int)nid) % ksocknal_data.ksnd_peer_hash_size;

        return &ksocknal_data.ksnd_peers[hash];
}

static inline void
ksocknal_conn_addref(ksock_conn_t *conn)
{
        LASSERT(atomic_read(&conn->ksnc_conn_refcount) > 0);
        atomic_inc(&conn->ksnc_conn_refcount);
}

extern void ksocknal_queue_zombie_conn(ksock_conn_t *conn);
extern void ksocknal_finalize_zcreq(ksock_conn_t *conn);

static inline void
ksocknal_conn_decref(ksock_conn_t *conn)
{
        LASSERT(atomic_read(&conn->ksnc_conn_refcount) > 0);
        if (atomic_dec_and_test(&conn->ksnc_conn_refcount))
                ksocknal_queue_zombie_conn(conn);
}

static inline int
ksocknal_connsock_addref(ksock_conn_t *conn)
{
        int   rc = -ESHUTDOWN;

        read_lock(&ksocknal_data.ksnd_global_lock);
        if (!conn->ksnc_closing) {
                LASSERT(atomic_read(&conn->ksnc_sock_refcount) > 0);
                atomic_inc(&conn->ksnc_sock_refcount);
                rc = 0;
        }
        read_unlock(&ksocknal_data.ksnd_global_lock);

        return rc;
}

static inline void
ksocknal_connsock_decref(ksock_conn_t *conn)
{
        LASSERT(atomic_read(&conn->ksnc_sock_refcount) > 0);
        if (atomic_dec_and_test(&conn->ksnc_sock_refcount)) {
                LASSERT(conn->ksnc_closing);
                libcfs_sock_release(conn->ksnc_sock);
                conn->ksnc_sock = NULL;
                ksocknal_finalize_zcreq(conn);
        }
}

static inline void
ksocknal_tx_addref(ksock_tx_t *tx)
{
        LASSERT(atomic_read(&tx->tx_refcount) > 0);
        atomic_inc(&tx->tx_refcount);
}

extern void ksocknal_tx_prep(ksock_conn_t *, ksock_tx_t *tx);
extern void ksocknal_tx_done(lnet_ni_t *ni, ksock_tx_t *tx);

static inline void
ksocknal_tx_decref(ksock_tx_t *tx)
{
        LASSERT(atomic_read(&tx->tx_refcount) > 0);
        if (atomic_dec_and_test(&tx->tx_refcount))
                ksocknal_tx_done(NULL, tx);
}

static inline void
ksocknal_route_addref(ksock_route_t *route)
{
        LASSERT(atomic_read(&route->ksnr_refcount) > 0);
        atomic_inc(&route->ksnr_refcount);
}

extern void ksocknal_destroy_route(ksock_route_t *route);

static inline void
ksocknal_route_decref(ksock_route_t *route)
{
        LASSERT(atomic_read(&route->ksnr_refcount) > 0);
        if (atomic_dec_and_test(&route->ksnr_refcount))
                ksocknal_destroy_route(route);
}

static inline void
ksocknal_peer_addref(ksock_peer_t *peer)
{
        LASSERT(atomic_read(&peer->ksnp_refcount) > 0);
        atomic_inc(&peer->ksnp_refcount);
}

extern void ksocknal_destroy_peer(ksock_peer_t *peer);

static inline void
ksocknal_peer_decref(ksock_peer_t *peer)
{
        LASSERT(atomic_read(&peer->ksnp_refcount) > 0);
        if (atomic_dec_and_test(&peer->ksnp_refcount))
                ksocknal_destroy_peer(peer);
}

int ksocknal_startup(lnet_ni_t *ni);
void ksocknal_shutdown(lnet_ni_t *ni);
int ksocknal_ctl(lnet_ni_t *ni, unsigned int cmd, void *arg);
int ksocknal_send(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg);
int ksocknal_recv(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg,
                  int delayed, unsigned int niov,
                  struct kvec *iov, lnet_kiov_t *kiov,
                  unsigned int offset, unsigned int mlen, unsigned int rlen);
int ksocknal_accept(lnet_ni_t *ni, struct socket *sock);

extern int ksocknal_add_peer(lnet_ni_t *ni, lnet_process_id_t id, __u32 ip, int port);
extern ksock_peer_t *ksocknal_find_peer_locked(lnet_ni_t *ni, lnet_process_id_t id);
extern ksock_peer_t *ksocknal_find_peer(lnet_ni_t *ni, lnet_process_id_t id);
extern void ksocknal_peer_failed(ksock_peer_t *peer);
extern int ksocknal_create_conn(lnet_ni_t *ni, ksock_route_t *route,
                                 struct socket *sock, int type);
extern void ksocknal_close_conn_locked(ksock_conn_t *conn, int why);
extern void ksocknal_terminate_conn(ksock_conn_t *conn);
extern void ksocknal_destroy_conn(ksock_conn_t *conn);
extern int  ksocknal_close_peer_conns_locked(ksock_peer_t *peer,
                                              __u32 ipaddr, int why);
extern int ksocknal_close_conn_and_siblings(ksock_conn_t *conn, int why);
extern int ksocknal_close_matching_conns(lnet_process_id_t id, __u32 ipaddr);
extern ksock_conn_t *ksocknal_find_conn_locked(ksock_peer_t *peer,
                                               ksock_tx_t *tx, int nonblk);

extern int  ksocknal_launch_packet(lnet_ni_t *ni, ksock_tx_t *tx,
                                   lnet_process_id_t id);
extern ksock_tx_t *ksocknal_alloc_tx(int type, int size);
extern void ksocknal_free_tx(ksock_tx_t *tx);
extern ksock_tx_t *ksocknal_alloc_tx_noop(__u64 cookie, int nonblk);
extern void ksocknal_next_tx_carrier(ksock_conn_t *conn);
extern void ksocknal_queue_tx_locked(ksock_tx_t *tx, ksock_conn_t *conn);
extern void ksocknal_txlist_done(lnet_ni_t *ni, struct list_head *txlist,
                                  int error);
extern void ksocknal_notify(lnet_ni_t *ni, lnet_nid_t gw_nid, int alive);
extern void ksocknal_query(struct lnet_ni *ni, lnet_nid_t nid, unsigned long *when);
extern int ksocknal_thread_start(int (*fn)(void *arg), void *arg, char *name);
extern void ksocknal_thread_fini(void);
extern void ksocknal_launch_all_connections_locked(ksock_peer_t *peer);
extern ksock_route_t *ksocknal_find_connectable_route_locked(ksock_peer_t *peer);
extern ksock_route_t *ksocknal_find_connecting_route_locked(ksock_peer_t *peer);
extern int ksocknal_new_packet(ksock_conn_t *conn, int skip);
extern int ksocknal_scheduler(void *arg);
extern int ksocknal_connd(void *arg);
extern int ksocknal_reaper(void *arg);
extern int ksocknal_send_hello(lnet_ni_t *ni, ksock_conn_t *conn,
                                lnet_nid_t peer_nid, ksock_hello_msg_t *hello);
extern int ksocknal_recv_hello(lnet_ni_t *ni, ksock_conn_t *conn,
                                ksock_hello_msg_t *hello, lnet_process_id_t *id,
                                __u64 *incarnation);
extern void ksocknal_read_callback(ksock_conn_t *conn);
extern void ksocknal_write_callback(ksock_conn_t *conn);

extern int ksocknal_lib_zc_capable(ksock_conn_t *conn);
extern void ksocknal_lib_save_callback(struct socket *sock, ksock_conn_t *conn);
extern void ksocknal_lib_set_callback(struct socket *sock,  ksock_conn_t *conn);
extern void ksocknal_lib_reset_callback(struct socket *sock, ksock_conn_t *conn);
extern void ksocknal_lib_push_conn(ksock_conn_t *conn);
extern int ksocknal_lib_get_conn_addrs(ksock_conn_t *conn);
extern int ksocknal_lib_setup_sock(struct socket *so);
extern int ksocknal_lib_send_iov(ksock_conn_t *conn, ksock_tx_t *tx);
extern int ksocknal_lib_send_kiov(ksock_conn_t *conn, ksock_tx_t *tx);
extern void ksocknal_lib_eager_ack(ksock_conn_t *conn);
extern int ksocknal_lib_recv_iov(ksock_conn_t *conn);
extern int ksocknal_lib_recv_kiov(ksock_conn_t *conn);
extern int ksocknal_lib_get_conn_tunables(ksock_conn_t *conn, int *txmem,
                                           int *rxmem, int *nagle);

extern int ksocknal_tunables_init(void);

extern void ksocknal_lib_csum_tx(ksock_tx_t *tx);

extern int ksocknal_lib_memory_pressure(ksock_conn_t *conn);
extern int ksocknal_lib_bind_thread_to_cpu(int id);